1. Field of the Invention
The present invention relates to an image forming apparatus such as an electronic copying machine having, e.g., an automatic document feeder (ADF) and a sorting unit.
2. Description of the Related Art
In a conventional electronic copying machine, in order to improve the efficiency of various types of copy operations, a return automatic document feeder designed for single-sided or double-sided documents and a sorter for automatically performing a collect operation (sort operation, including a stack operation, are connected to the main body.
The need for such an electronic copying machine has recently increased with an increase in the amount of documents to be processed and a demand for less processing time.
In an electronic copying machine having a return automatic document feeder and a sorter, shown, for example, in U.S. Pat. No. 4,913,426, a sort mode is not selected unless an operator designates it by operating a specific key.
When a plurality of paper sheets for copy processing (a plurality of copies) are set, and a copy operation is to be performed by using an ADF, however, there is a considerably higher probability that an operator selects the sort mode. In this case, no problem will occur even if the sort mode is selected in a case where a single copy is to be formed. That is, the probability of performing the copy operation is substantially great in a case when the sort mode is selected. However, since the sort mode is never selected when no instruction is made by the operation. It is not possible to have a situation in which the operator tends to forget the setting of the sort mode.
As described above, in a conventional electric copying machine, it is difficult to properly determine the need for the sort mode and automatically set the sort mode.